Melanoma is an aggressive malignancy associated with five-year survival rates under 5% in patients with metastatic disease.1 Despite successful excision of the primary lesion, a five-year survival of only 68% is expected in cases of primary melanoma greater than 2 mm in thickness.5, 6 Increasing depth of the primary tumor and the presence of high risk histopathology are predictive of recurrence across populations, but do not accurately assess risk in individual patients.7 Sentinel lymph node biopsy (SLNB) is an invasive procedure that offers limited prognostic information and has no proven survival benefit.8 Improved biomarkers are needed to identify patients at high risk for recurrence and death.
Expression profiling has never been systematically performed in formalin-fixed, paraffin-embedded (FFPE) primary melanoma.9 In contrast, Oncotype DX measures the expression of a 21-gene panel and offers prognostic information for patients with breast cancer.10 The development of similar biomarkers in melanoma has been limited due in part to the clinical standard of entire tumor fixation in formalin which leads to low yields of extractable RNA and limits the quality of RNA available for molecular studies. As a result, studies of primary melanoma have relied on cell lines, limited supplies of frozen tissue, or focused on profiling microRNA, which is less subject to degradation.11-17 Even in rare cases where frozen tissue is available, RNA extraction is difficult due to the fibrous nature of cutaneous tissues.9, 12 
Thus, there is a need for suitable methods and markers for providing prognostic information related to melanoma.